Universal Greenberger-Horne-Zeilinger-state analyzer based on two-photon polarization parity detection

We present a universal analyzer for the three-particle Greenberger-Horne-Zeilinger (GHZ) states with quantum nondemolition parity detectors and linear-optics elements. In our scheme, all of the three-photon GHZ states can be discriminated with nearly unity probability in the regime of weak nonlinearity feasible at the present state of the art experimentally. We also show that our scheme can be easily extended to the analysis of the multi-particle GHZ states.

Generation and discrimination of Greenberger-Horne-Zeilinger states using dipole-induced transparency in a cavity-waveguide system

We propose an efficient scheme to build an arbitrary multipartite Greenberger-Horne-Zeilinger state and discriminate all the universal Greenberger-Horne-Zeilinger states using parity measurement based on dipole-induced transparency in a cavity-waveguide system. A prominent advantage is that initial entangled states remain after nondetective identification and they can be used for successive tasks. We analyze the performance and possible errors of the required single-qubit rotations and emphasize that the scheme is reliable and can satisfy the current experimental technology.

1736～1999年西安与汉中地区年冬季平均气温序列重建

基于现代气象资料所建立的西安、汉中地区冬季降雪天数与年冬季平均气温之间的相关关系,根据清代档案所记载的西安与汉中地区冬季降雪日数,恢复了西安与汉中地区1736～1910年的年冬季平均气温,重建了1736～1999年西安与汉中地区年冬季平均气温序列。序列分析表明,这两个地区年冬季平均气温变化趋势一致:18世纪和20世纪为暖期,19世纪为冷期,且20世纪的增暖趋势明显。与利用树轮重建的镇安初春(3～4月)温度序列对比分析表明:西安、汉中地区冬季平均气温与镇安初春温度的低频变化趋势基本一致,但镇安较西安与汉中有

1736年以来长江中下游梅雨变化

利用清代雨雪分寸资料,复原了1736~1911年长江中下游地区的梅雨入出日期、雨期长度,重建了1736年以来长江中下游地区梅雨雨量变化序列,分析了梅雨的变化特征;并根据梅雨期长度与东亚夏季风指数之间的关系,分析了1736年以来东亚夏季风的强弱及与之对应的雨带位置阶段性变化特征.结果表明:长江中下游地区入、出梅日期及雨期长度均存在明显的年-年代际变化,雨期长度除具有2,7~8,20~30及40a的年际与年代际周期外,还具有百年波动的信号.1736年以来,雨期长短、中国东部季风雨带位置移动与东亚夏季风强弱变化